Al,
Check out IPC-2222, Table 9-3, for the answer to your question about lead:hole ratio. Lead size to hole diameter relationship is based on min hole size to max lead dia, and max hole size to min lead diameter.
The answer to pad size increases: probably. An annular needs to be of sufficient size to permit a good solder fillet to form and meet minimum annular ring requirements, and not too large so as not to allow heat buildup from the soldering to damage the part above board. (Don't laugh people, we've had this happen before; must be the board designer's fault, right?) Some designers also consider the size of the trace terminating at the pad.
Best Rgds,
Roger M. Stoops, CID
Trimble Navigation Ltd., Dayton, OH, USA
Ph: 937.233.8921 or 937.233.4574 ext 288
Fax: 937.233.7511
It's FRIDAY people; are we ready to go home yet? (I was ready yesterday...)
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Friday, May 16, 2003 10:50 AM
To: [log in to unmask]
Subject: [TN] Lead:Hole Ratio and Annular Ring Size
Hello Technetters,
I'm looking for industry specs (or just other technetters experience) on
lead:hole ratio and annular ring (pad) size when using pth dc converters
(Lucent, Tyco, Ericsson, etc.) that have lead diameters that are .040",
.062", .080, and/or .180".
Does the standard .015"-.017" lead:hole ratio still apply to these large
leads? And should the pad size increase linearly with the increase in lead
diameter?
Thanks in advance as always,
See some of you at NEPCON East?
Al Kreplick
Sr. Manufacturing Engineer
Teradyne, Inc.
500 Riverpark Drive
Mail Stop NR500 1-1
North Reading, MA 01864
Tel: 978-370-1726
Fax: 734-661-5352
Pager: 888-561-6485
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